1. Field of the Invention
The present invention relates to molded concrete blocks for masonry construction, and specifically to mortarless interlocking blocks for such use.
2. Prior Art
In the prior art, concrete blocks have been molded with tongue and groove interlocking provisions in their top and bottom surfaces and end surfaces for mortared block systems, as shown in U.S. Pat. No. 3,256,657 to Phipps, U.S. Pat. No. 811,534 to Akers, et al., U.S. Pat. No. 2,482,719 to Rigaumont, and U.S. Pat. No. 2,452,463 to Herbert, as well as for mortarless block systems, as shown in U.S. Pat. No. 3,962,842 to Wilhelm, and British Pat. No. 166,623 to Christmas.
Each of the above-named patents discloses special corner blocks for its specific interlocking system; West German Pat. No. 2,200,015 to Bender discloses special corner blocks, but is without interlocking features on the upper and lower block surfaces and does not provide for reinforcing rods.
No known prior mortarless block construction system provides secure T-intersections and crossing-wall intersections.
Bond beam courses are made up of channel-like blocks which receive steel reinforcing rods and grouting to form a horizontal beam to strengthen the structure, as in French Pat. No. 2,346,514 to Bastianelli. French Pat. No. 546,143 to Vaux discloses an interlocking concrete block having end webs which may be broken away to receive horizontal reinforcing rods. Similarly, U.S. Pat. No. 989,677 to Wiederholdt shows break-away end webs in a building tile to be secured to adjacent tiles by interior grouting only. No prior block construction provides for reinforcing the corners of bond beam courses except by extensive on-site modification.